JP7052610B2 - Power converter - Google Patents

Description

The technology disclosed herein relates to a power converter in which a cooler and a circuit board to which a pipe for supplying or discharging a refrigerant is connected are housed in a case.

Among the power conversion devices installed in automobiles, etc., a cooler using a liquid refrigerant for cooling the power card or the like housed in the case of the power conversion device is housed in the case. There is. In the device disclosed in Patent Document 1, a refrigerant outlet and a refrigerant inlet are provided on one side of a cooler housed in a case of a power conversion device, and a cooling pipe is connected to each of them.

Japanese Unexamined Patent Publication No. 2011-182630

A circuit board with a circuit that controls the power card may be placed at the bottom of the case. On the other hand, if the cooling pipe is removed from the cooler during maintenance of the power conversion device, the liquid refrigerant remaining in the cooler may leak into the case. If the leaked liquid refrigerant drips onto a circuit board or the like located below, it may induce a circuit failure.

The power conversion device disclosed herein comprises a case. The power converter comprises a laminated cooler that is housed in a case and has a refrigerant inlet / outlet on the side. A circuit board is located below the laminated cooler in the case. The power conversion device is connected to a refrigerant inlet / outlet and includes a pipe for supplying or discharging the refrigerant. The pipe and the refrigerant inlet / outlet are connected via a gasket. The case comprises a partition plate extending from the inner surface of its side wall between the laminated cooler and the circuit board. A part of the upper surface of the partition plate is provided with a predetermined area separated from the surroundings by a side wall closed when viewed from vertically above the partition plate. When the case and the laminated cooler are viewed from above, the refrigerant inlet / outlet is located in the predetermined area, and the predetermined area and a part of the circuit board overlap with each other.

If the pipe is removed from the laminated cooler during maintenance of the power converter, the liquid refrigerant remaining in the cooler may leak into the case. Even in such a case, the leaked refrigerant can be held in a predetermined region separated from the surroundings by the side wall, and the refrigerant can be prevented from moving out of the predetermined region. As a result, the leaked refrigerant does not drip onto the circuit board, so that it is possible to prevent the circuit board from failing.

It is a perspective view which shows the device layout in the front compartment of a hybrid vehicle. It is a side view of the power control unit fixed on the transaxle. It is an exploded perspective view of a power control unit. It is a top view of the lower case. FIG. 3 is a partially enlarged view of a cross-sectional view taken along the line VV of FIG. 4. FIG. 4 is a cross-sectional view taken along the line VI-VI of FIG.

(In-vehicle structure of power control unit)
FIG. 1 is a perspective view showing a device layout in the front compartment 90 of the hybrid vehicle 100. In the coordinate system in the figure, the positive direction of the F axis indicates the front of the vehicle, and the positive direction of the V axis indicates the upper side of the vehicle. The positive direction of the H axis indicates the left side of the vehicle. In addition, in FIG. 1, the device mounted on the front compartment 90 is schematically drawn.

The front compartment 90 houses an engine 95, a transaxle 31, a power control unit 2, a radiator 96, an auxiliary battery 5, and the like. Various other devices are housed in the front compartment 90, but their illustration and description are omitted.

The power control unit 2 is fixed to the upper surface of the transaxle 31. The power control unit 2 is a device that boosts the DC power of a main battery (not shown) and converts the boosted DC power into AC power suitable for driving a motor.

FIG. 2 shows a side view of the power control unit 2 fixed to the upper surface 31a of the transaxle 31. The upper surface 31a of the transaxle 31 is inclined forward downward, and the power control unit 2 fixed on the upper surface 31a is also fixed in the forward downward posture. The XYZ coordinate system of FIG. 2 is a coordinate system for the power control unit 2, the X axis extends parallel to the bottom surface of the case of the power control unit 2, and the Z axis extends parallel to the rear surface of the case. , The Y-axis extends along the vehicle width direction. The power control unit 2 is fixed above the upper surface 31a of the transaxle 31 by the front bracket 93 and the rear bracket 94.

The case 12 of the power control unit 2 is divided into an upper cover 12c, an upper case 12b, a lower case 12a, and a lower cover 13 in the vertical direction. The upper case 12b and the lower case 12a are fixed to each other in the vertical direction by a plurality of bolts 18. In FIG. 2, the refrigerant pipe 45, the refrigerant discharge pipe 78, the refrigerant supply pipe 79, etc., which will be described later, are not shown.

(Structure of power control unit 2)
FIG. 3 is an exploded perspective view of the power control unit 2. As shown in FIG. 3, the case 12 of the power control unit 2 is divided into a lower case 12a which is an inverter case and an upper case 12b which is a converter case. The lower case 12a and the upper case 12b are made of aluminum.

The lower case 12a is a rectangular parallelepiped container. The lower case 12a includes a partition plate 12a1 and a side wall 12a2, and the upper surface and the lower surface are open. The partition plate 12a1 extends horizontally from the inner surface of the side wall 12a2. A cooling unit 20, a circuit board 60, an inverter circuit (not shown), and the like are housed in the lower case 12a. The cooling unit 20 is housed through the upper opening of the lower case 12a, and the circuit board 60 is housed through the lower opening. That is, the cooling unit 20 is located above the partition plate 12a1, and the circuit board 60 is located below the partition plate 12a1. In FIG. 3, electrical components such as reactors and smoothing capacitors are not shown. Further, in FIG. 3, the lower cover 13 (see FIG. 2) that closes the lower opening of the lower case 12a is not shown.

A through hole 76 to which the refrigerant discharge pipe 78 is connected, a through hole 16 to which the joint pipe 30 is connected, and a bolt hole 82 are formed on the side surface 14a of the lower case 12a. In the present embodiment, the normal direction of the side surface 14a is defined as the X-axis, and the lower left of FIG. 3 is defined as the X-axis positive direction. The plane orthogonal to the X-axis is defined as the YZ plane, and the vertically upward direction in FIG. 3 is defined as the Z-axis positive direction. The axis orthogonal to the X-axis and the Z-axis is defined as the Y-axis, and the lower right direction in FIG. 3 is defined as the Y-axis positive direction. The XYZ axes in FIGS. 4 to 6, which will be described later, correspond to the XYZ axes in FIG.

The cooling unit 20 housed in the lower case 12a includes a plurality of power cards 22 having semiconductor elements inside, and a plurality of cooling plates 21 through which the refrigerant passes. The plurality of power cards 22 and the plurality of cooling plates 21 are alternately laminated one by one, and the power cards 22 are sandwiched between the adjacent cooling plates 21. The adjacent cooling plates 21 are connected by connecting pipes 25a and 25b. The tubes 23 and 24 are connected to the cooling plate 21 at the end in the positive direction of the X-axis. The tube 23 is arranged so as to overlap the connecting pipe 25a when viewed from the X direction, and the tube 24 is arranged so as to overlap the connecting pipe 25b when viewed from the X direction. A liquid refrigerant is supplied to the cooling unit 20 through the tube 23. The refrigerant supplied from the tube 23 is distributed to all the cooling plates 21 through the connecting pipe 25a. The refrigerant absorbs the heat of the power card 22 while passing through the cooling plate 21. The refrigerant that has absorbed heat is discharged from the cooling unit 20 through the connecting pipe 25b and the tube 24.

The circuit board 60 is located below the cooling unit 20 with the partition plate 12a1 interposed therebetween. A control circuit for controlling the semiconductor element of the power card 22 is mounted on the circuit board 60. A large number of electronic components such as semiconductor chips are mounted on the upper surface of the circuit board 60, but their illustrations are omitted. The partition plate 12a1 is provided with an opening 12aO, and the power card 22 and the circuit board 60 are electrically connected to each other through the opening 12aO by a signal pin (not shown).

The outer shape of the upper case 12b is a rectangular parallelepiped similar to the lower case 12a. A cooler, other electrical components (not shown), and a cooler for cooling them are housed inside the upper case 12b, but these are not shown in FIG. 3, and the upper case 12b is simply simplified. It is represented by a rectangular parallelepiped. In FIG. 3, the upper cover 12c (see FIG. 2) covering the upper opening (not shown) of the upper case 12b is also omitted.

Similar to the lower case 12a, the upper case 12b is connected to the through hole 17 to which the upper end of the refrigerant pipe 45 is connected and the refrigerant supply pipe 79 to the side surface 14b parallel to the YZ plane on the positive direction side of the X axis. A through hole 77 and a bolt hole 83 are formed. When the lower case 12a and the upper case 12b are combined, the side surface 14a and the side surface 14b are integrated into one side surface 14, and the through hole 17 is located in the Z-axis positive direction of the through hole 16. Similarly, the through hole 77 is located in the Z-axis positive direction of the through hole 76.

The lower end of the U-shaped refrigerant pipe 45 is connected to the through hole 16 of the lower case 12a via the joint pipe 30, and the upper end of the refrigerant pipe 45 is connected to the through hole 17 of the upper case 12b. The refrigerant supplied from the refrigerant circulation device (not shown) flows into the cooler (not shown) of the upper case 12b through the refrigerant supply pipe 79. The refrigerant that has passed through the cooler is supplied to the cooling unit 20 from the through hole 17 of the upper case 12b through the refrigerant pipe 45, through the joint pipe 30 and the through hole 16 of the lower case 12a. The refrigerant that has passed through the cooling unit 20 is discharged to the outside of the case 12 through the through hole 76 of the lower case 12a. The discharged refrigerant returns to the refrigerant circulation device (not shown) through the refrigerant discharge pipe 78.

The joint pipe 30 has a cylindrical shape and has a flange at one end of the cylinder. The outer peripheral surface of the joint pipe 30 other than the flange is formed so as to fit into the inner peripheral surface of the through hole 16. The joint pipe 30 is formed so that the flange is in contact with the side surface 14a of the lower case 12a when fitted into the through hole 16. One end of the refrigerant pipe 45 is connected to the through hole 17 of the upper case 12b, and the other end is connected to the through hole 16 of the lower case 12a via the joint pipe 30. The refrigerant pipe 45 guides the refrigerant discharged from the cooler through the through hole 17 to the cooling unit 20 inside the lower case 12a through the through hole 16. A flange 42a and a rib 41a are provided at one end of the refrigerant pipe 45, and a flange 42b and a rib 41b are provided at the other end.

The flange surface of the flange 42a facing the negative direction of the X-axis is in contact with the side surface 14a of the lower case 12a. The rib 41a extends from the flange 42a in the negative direction of the Z axis. The rib 41a is formed with a hole through which the bolt 81 penetrates. The bolt 81 passes through the hole of the rib 41a and is screwed into the female thread groove of the bolt hole 82. As a result, the refrigerant pipe 45 is fixed to the lower case 12a. The refrigerant pipe 45 is similarly fixed to the upper case 12b.

(Specific structure of lower case 12a)
FIG. 4 shows a top view of the lower case 12a. FIG. 4 shows a state in which the cooling unit 20 and the circuit board 60 are housed in the lower case 12a. In FIG. 4, the cooling unit 20 is shown by a dotted line, and the circuit board 60 is shown by a alternate long and short dash line. As shown in FIG. 4, the lower case 12a includes predetermined regions R1 and R2. The predetermined regions R1 and R2 are formed on a part of the upper surface of the partition plate 12a1 of the lower case 12a. In FIG. 4, predetermined regions R1 and R2 are shown by hatching to help understanding. As described above, the partition plate 12a1 of the lower case 12a is formed with an opening 12aO. The circuit board 60 is located below the cooling unit 20 with the partition plate 12a1 interposed therebetween.

A closed side wall is formed by the rib side walls SW11 and SW12 formed on the partition plate 12a1 and the side wall 12a2 of the lower case 12a. The predetermined area R1 is completely separated from the surroundings by this closed side wall. In other words, the predetermined region R1 has a shape capable of storing a liquid like a tub. The rib side wall SW11 and SW12 are ribs integrally formed with the partition plate 12a1 and the side wall 12a2 of the lower case 12a. Since it is only necessary to add the ribs that function as the rib side walls SW11 and SW12, the cost increase for forming the predetermined region R1 is small. Further, a side wall closed by the rib side walls SW21 and SW22 formed on the partition plate 12a1 and the side wall 12a2 of the lower case 12a is formed. The predetermined area R2 is completely separated from the surroundings by this closed side wall. Since the function of the predetermined area R2 is the same as the function of the predetermined area R1, the description thereof will be omitted.

In FIG. 4, when the lower case 12a and the cooling unit 20 are viewed from above (Z-axis positive direction), a region near the tip of the tube 23, which is a refrigerant inlet / outlet, is included in the predetermined region R1. Specifically, the region in which the gasket 85, which will be described later, is fitted in the tube 23 is located in the predetermined region R1. Similarly, a region near the tip of the tube 24, which is a refrigerant inlet / outlet, is included in the predetermined region R2. Further, the predetermined region R1 overlaps with a part of the circuit board 60.

FIG. 5 shows a partially enlarged view of a cross-sectional view taken along the line VV of FIG. FIG. 5 is a cross-sectional view in a state where the refrigerant pipe 45 and the joint pipe 30 are connected to the tube 23. As shown in FIG. 5, in the power control unit 2, the connecting portion of each member is sealed by a plurality of resin gaskets so that the refrigerant does not leak to the outside. Specifically, the gasket 86 is arranged between the flange of the joint pipe 30 and the side surface 14a of the lower case 12a. A gasket 87 is arranged between the inner peripheral surface of the joint pipe 30 and the outer peripheral surface of the refrigerant pipe 45 that fits with the joint pipe 30. A gasket 85 is arranged between the inner peripheral surface of the joint pipe 30 and the tube 23 of the cooling unit 20. As a result, the refrigerant pipe 45 and the tip of the tube 23, which is the inlet / outlet of the refrigerant, are connected to each other without a gap via a gasket.

As shown in FIG. 5, a predetermined region R1 is provided below the joint pipe 30 and the tube 23 (in the negative direction of the Z axis). The predetermined region R1 is a region completely separated from the periphery by the rib side wall SW12 and the side wall of the lower case 12a. When the cooling unit 20 is viewed from above (Z-axis positive direction), the gasket 85 of the tube 23 is included in the predetermined region R1.

FIG. 6 shows a cross-sectional view taken along the line VI-VI of FIG. In FIG. 6, the positions of the tube 23 and the tube 24 are shown by dotted lines. As shown in FIG. 6, the lower case 12a includes predetermined regions R1 and R2. The predetermined region R1 is a region completely separated from the surroundings by the rib side wall SW11 and the side wall 12a2 of the lower case 12a. The predetermined region R2 is a region completely separated from the surroundings by the rib side wall SW21 and the side wall 12a2 of the lower case 12a. When the cooling unit 20 is viewed from above (Z-axis positive direction), the entire radial direction of the tube 23 is included in the predetermined region R1, and the entire radial direction of the tube 24 is included in the predetermined region R2. ing. When the cooling unit 20 is viewed from above (Z-axis positive direction), the predetermined regions R1 and R2 overlap with a part of the circuit board 60. The circuit board 60 is fixed to the partition plate 12a1 with bolts 61.

(Procedure for disassembling the refrigerant pipe)
A procedure for disassembling the refrigerant pipe 45 at the time of maintenance of the power control unit 2 will be described. First, by purging the air, the refrigerant is discharged from the inside of the cooling unit 20 and the refrigerant pipe 45. Next, the refrigerant pipe 45 is removed from the case 12. At this time, the gasket 85 remains on the tube 23 side. This is because the holding force of the refrigerant pipe 45 in the pull-out direction (that is, the positive direction of the X-axis) is more the holding force of the seal between the joint pipe 30 and the gasket 85 than the holding force of the seal between the gasket 85 and the tube 23. This is because it is designed so that the holding force is larger. This makes it possible to prevent the refrigerant from leaking into the lower case 12a. Next, the upper case 12b is removed. As a result, the cooling unit 20 can be accessed from above (in the positive direction of the Z axis). Remove the gasket 85 from the tube 23. This completes the disassembly of the refrigerant pipe 45.

(effect)
When the gasket 85 is removed from the tube 23 at the time of disassembling the refrigerant pipe 45, the refrigerant remaining in the cooling unit 20 may leak into the lower case 12a. Even in such a case, the leaked refrigerant can be received in the predetermined regions R1 and R2 (see FIGS. 4 to 6). Further, since the predetermined regions R1 and R2 have a tub-like shape, it is possible to hold the received refrigerant and prevent the refrigerant from moving to another place. As a result, the leaked refrigerant does not drip onto the circuit board 60 from the opening 12aO of the partition plate 12a1 of the lower case 12a, so that it is possible to prevent the circuit board 60 from failing. ..

The power control unit 2 of the present specification has a structure in which the lower case 12a and the upper case 12b can be separated. As a result, by removing the upper case 12b, the cooling unit 20 arranged in the lower case 12a can be accessed from above (in the positive direction of the Z axis). Therefore, it is possible to easily remove the refrigerant held in the predetermined regions R1 and R2.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples exemplified above. The technical elements described herein or in the drawings exhibit their technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques exemplified in the present specification or the drawings can achieve a plurality of purposes at the same time, and achieving one of the purposes itself has technical usefulness.

(Modification example)
The connection structure between the refrigerant pipe 45 and the cooling unit 20 in the present specification is an example. For example, the refrigerant pipe 45 and the tube 23 of the cooling unit 20 may be connected without going through the joint pipe 30.

The shapes and areas of the predetermined regions R1 and R2 in the top view may be various. Further, in the present specification, an example in which a side wall closed by a rib side wall and a side wall of the lower case 12a is formed is given, but the present invention is not limited to this form. For example, a closed side wall may be formed only by the rib side wall.

In the above embodiment, the power control unit 2 including the connection structure between the refrigerant pipe 45 and the cooling unit 20 has been described as an example. However, the device to which the connection structure connects the refrigerant can be variously modified, and the power control unit. It may be a device other than 2.

In the above embodiment, the connection structure between the refrigerant pipe 45 and the cooling unit 20 has a flange 42a and a rib 41a, but the configuration of this connection structure can be variously modified.

The lower case 12a is an example of a case. The cooling unit 20 is an example of a laminated cooler. The refrigerant pipe 45 is an example of a pipe.

2 ... Power control unit 12 ... Case 12a ... Lower case 12b ... Upper case 20 ... Cooling unit 23, 24 ... Tube 30 ... Joint pipe 45 ... Refrigerant pipe 60 ... Circuit board 85, 86, 87, 88 ... Gaskets R1, R2 ... Predetermined area SW11, SW12, SW21, SW22 ... Rib side wall

Claims (1)

A case, a laminated cooler housed in the case and having a refrigerant inlet / outlet on the side surface, a pipe connected to the refrigerant inlet / outlet to supply or discharge a refrigerant, and a laminated cooler housed in the case. A power converter with a circuit board located below the vessel,
The pipe and the refrigerant inlet / outlet are connected via a gasket.
The case includes a partition plate extending from the inner surface of the side wall between the laminated cooler and the circuit board, and a part of the upper surface of the partition plate is viewed from vertically above the partition plate. A predetermined area is provided that is separated from the surroundings by a side wall that is closed when it is closed.
A power conversion device in which the refrigerant inlet / outlet is located in the predetermined region and the predetermined region overlaps a part of the circuit board when the case and the laminated cooler are viewed from above.

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